A program of work is underway centered on study of various aspects of acute toxic liver injury. One line of work involves study of the metabolism of CCl4 in vitro by a cell-free system based on isolated rat liver microsomes, which can convert up to 30% of added CCl4 to CHCl3. This system is being used to answer fundamental questions related to lipid peroxidation as a link between CCl4 metabolism and the liver cell injury produced by CCl4. Another line of work involves re-investigation of possible peroxidation of liver mitochondrial lipids in acute experimental alcoholic hepatitis. A new method will be applied to this study. It is based on formation of Diels-Alder adducts with lipid conjugated dienes. A further line of work is concerned with consequences to the organism as a whole as a result of acute toxic liver injury. This line of work involves study of the toxicity of lipid hydroperoxides and their breakdown products, and possible involvement of low molecular weight thiol compounds in the general deterioration of the animal with a failing liver.